Theoretical analysis of the cyclic cascade model reveals that in addition to the properties described in the previous report, the modification and demodification of the last interconvertible enzyme in the cascade proceeds with a lag, and this lag time dependent on the number of cycles involved in the cascade. The magnitude of the rate amplification is dependent on the number of cycles, kinetic constants, and the concentration of both effectors and enzymes involved. The adenylylation-deadenylylation of glutamine synthetase system and the phosphorylation-dephosphorylation of protein by c-AMP-dependent protein kinase and phosphatase is being studied for the verification of the cyclic cascade model. (2) The irreversible inhibition of glutamine synthetase by L-methionine-S-sulfoximine reveals the homologous subunit interaction in the enzyme. The catalytic cycle for alkaline phosphatase was elucidated; and the catalytic cycle for the adenylylated glutamine synthetase using the fluorescence signal of 2-aza-adenylylated enzyme is being investigated. (3) Kinetic studies of L-Ala binding reveal that the tight binding of L-Ala to the Mn (II) activated unadenylylated glutamine synthetase is primarily due to the strong synergism between ADP and L-Ala. Other studies included CRO protein-DNA interaction and actomyosin ATPase.